Direct-acting engine.



G. L. BA'DGER.

' DIRECT ACTING ENGINE.

APPLIUATIONTILED JUNI: 21. 1901.

998,563. l I Panueamy 18,1911.

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G. L BADGBR. DIBEGT ACTING ENGINE.

PILIOATION FILED JUNE 21, 1907. 998,563. l I Patented July 18,1911.

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fil .2 /.9" 9 an 2.25' w/ @Wig 'B/f Ewa @43g 27 y 7 @24 III H "WlZIN/@765265: j# I 6L IHN/@Wwf GEORGE L. BADGER, OF GEUINCY,MASSACHUSETTS.

DIRECT-ACTING ENGINE.

ceases.

Specification of Letters Patent.

Application tiled .Tune 21, 190?.

Patented July 18. 1911. serial no. saacs.-

.To all 'ro/tom it may concern:

Be it known that l, Geenen L. Banana, citizen of the Umted States,residing at Quincy, in the county of Norfolk, State of lttassachusetts,have invented a certain new and useful Improvement in Direct-totingEngines, of which the following is a specification, reference being hadtherein to the accompanying drawings.

This invention relates to improven'ients in direct acting engines andfor illustration is shown in the accompanying drawings as applied to arock drill, although the invention is applicable to various otherpurposes and other types of engines.

The principal objects of the invention are to provide a piston valvewhich will prevent leak or waste of motive Huid past the surfaces whichclos-c or seal the admission and exhaust ports and which is adapted tobe wholly or partially actuated by fluid. pressure, and also adapted tobe wholly or in part mechanically ope 1ated.

t further object is to provide improved means for mechanically operatingthe valve which will move the latter' very rapidly from one position tothe other independent of the speed at which the piston may be moving.

ln apparatus of this character as is well known the stroke of the pistonis variable, depending to a great extent upon the speed at which thepiston is moving, the momentum of the piston and other moving partsconnected thereto carrying the piston beyond the point in the stroke atwhich the valve shifts to admit tluid to move the piston in theopposit-e direction. In some instances it desirable to obtain as great avariation in the length of stroke as possible, while in other cases itis desirable to maintain the length of stroke approximately uniform atvarying speeds. To accomplish the latter result it is necessary to avoida dead point in the stroke in order to prevent the piston from stoppingaltogether when it is moving slowly.

Fluid actuated valves whose movement is in dependent of, but controlledby, the movements of the piston are largely employed in apparatus ofthis character. he supply of tluid for actuating the valves is sometime.controlled directly by the piston, the latter acting as a valve toalternately open and close ports' in the walls of the cylinder leadingto the valve. Although this is the simplest manner of controlling thevalve, it is not desirable in every instance to employ a piston as longas is required to operate the valve in this manner, and the method hasthe disadvantage that as the cylinder and piston wear and allow thefluid to leak past the bearing surfaces the action of the valves becomessluggish and irregular. To overcome the objections above mentioned anauxiliary valve is sometimes employed, which is positively actuated 01controlled by the movements of the piston, the movement of the auxiliaryvalve controlling the ports leading respectively to opposite ends of themain valve to actuate the latter.

.Vith the novel valve herein shown and described l am enabled to obtainthe advantages of positively actuated valves and the flexibility offluid actuated valves without employing an auxiliary valve. I do notdepend upon the accuracy of the sliding tit of the convex surface of thevalve in the valve chamber to prevent a loss or waste of motive tiuid,except during the movement or travel ofthe valve. The admission andexhaust ports in the valve-casing which are connected with passages withthe cylinder are alternately opened and closed by the convex slidingsurfaces of the valve covering` or lapping over the port openings, butwhen the valve is at the limit of its movement in either direction thesupply of motive Huid to one end of the cylinder and the exhaustfrom theopposite end of the cylinder are sealed by the beveled seats of thevalve bearing on the beveled seats of the valve-casing. When the valveis moving from one end of the valve-'casing to the opposite end, thesupply of tiuid to one end of the cylinder is cut oft by one portion ofthe convex surface of the valve before the exhaust-portl from said endof the cylinder is uncovered by another portion of the convex surface ofthe valve and the only waste of tiuid through the exhaust ports is thatwhich may leak past the convex surface during the movemeut of the valve7and this movement of the valve is very rapid.

The invention will be fully understood from the following descriptiontaken in connection with the accompanying drawings,

and the novel features thereof are pointed out and clearly defined inthe claims at the close of the specification.

In the drawings,-Figure l is a longitudinal sectional elevation showingpart of a rock drill embodying the invention. The cylinder and pistonare broken away and the other parts are not shown as they form nonecessary part of the invention. Fig. 2 is an end view partly insection. Fig. 8 is a section on line 3 3 of Fig. 2.

The valve chest or casing is composed of three sections. The centralsection A is preferably made of cast metal and bolted to the cylinder'in the usual or in any suitable manner and is provided with the coredout passages A, A2, communicating with -passages B1, B2, leadingrespectively to opposite ends of the cylinder B and with the chambersaf, a2 in the heads A1, A1 which are fitted to the central section A ofthe valve-casing. Said heads are preferably made of material which maybe hardened to furnish durable seats for the valve. The central sectionA has an opening A9 adapted to be connected with a source of Huidpressure supply and a passage A11 communicates with the passages A12,A13 in the heads A3, A1 and permits fluid vpressure to enter the annularchambers A11, A11 and to pass to the chamber af, a2 when the valve is inthe proper position. The exhaust from the passages cl, a2 passestherefrom to the chamber A1G through chambers A11, A18 as shown in Fig.3 and to the atmosphere through passage A111. The heads A1, A1 arepreferably provided with passages A12, A2o leading respectively from theannular chambers A11, A15 to each end of thevalve-casing so that themotive Huid can pass to each end of the valve. The size or cross-sectionof these passages is determined by the manner in which the valve is tobe operated. If the. valve is to be wholly or partially actuated byfluid pressure, the size of the passages is made very small for thereason that will be hereinafter explained. If the valve is to beoperated mechanically without being supplemented by fluid pressure, saidpassages A12, A20 are made of comparatively large cross-section so thatthe pressure on each end of the valve will equalize and not interferewith the rapid movement of the valve. The passages A12, A21 arepreferably screw-threaded, or tapped, to receive the plugs A21, A22which have small holes or passages A21, A24 passing through them and pinvalves A21, A2S are provided by which the amount of fluid passingthrough the holes A22, A21 to each end of the valve may be regulatedwhen the valve is t0 be Wholly or partially actuated by liuid pressure,the pin valves being in threaded engagement with the plates C', C2 andhaving check nuts A211, A30.

The valve may be operated wholly by mechanical means by closing the pinvalves A21, A2S as shown in Fig. 3, in which case there will be no fluidpressure on the ends of the valve except that which may pass by theconvex surfaces of the portions ltl, E3 of the valve. To relieve thispressure, if any, the heads A3, A1 are provided with the passages J, J',leading from the ends of the valve to the cylinder as shown at K, K,which are, by the movements of the piston. alternately placed incommunication with the chamber A21,and through the passages A2, A1C andA1 with the atmosphere, thus relieving any pressure on the proper cud ofthe valve when it is in either position as hereafter more fullyexplained.

The passages J, J', are screw threaded in the heads A2`l A1, as shownclearly in Fig. l so that they may be plugged and conimunication fromthe end of the valve to the cylinder and to the atmosphere. cut off.then the passages J, J, are plugged, the plugs A21, A22 may be removedand the passages A12, A20 being of large area will permit the tiuid topass freely to and from the chambers at cach end of the valvey as it isshifted, and there will be no leak or waste of motive fluid and thevalve will beoperated wholly by mechanical means.

There are two seats A, A in the head A3 and two seats A1, A2 in the headA1. rThe plates C'. C2 are fitted respectively to either end of thevalve-easing and the whole bolted together by the three bolts D, D2, D2.rlhe central section A is provided with the openings A2, A10, to whichthe Huid pressure supply and the exhaust connections may be made. Thefluid pressure supply is preferably connected with the opening A for thereason hereinafter explained, but when used for some types of engines.the motion thereof may be reversed by admitting vtiuid aty A10 andexhausting at A2. A passage A11 is preferably cored through one side ofthe section A, as shown in Fig. 5l, connecting with passages A12, A11 inthe heads A2, A", and communicating with the annular chambers A11, A15therein. The passage A1O communicates by means of the passage A1G withthe annular chambers A11, A12 in the central section A of thevalvecasing.

The valve is formed in three parts E. E2, E1, which are held inassembled position by the bolt Ff. These parts are preferably hardened`then assembled and ground true on the centers of the bolt E1. using thelatter as an arbor. The dowels Fr, F. serve to locate the parts of thevalve in the same relation to each other when reasscmbling.

The valve is preferably provided with four bevel seating surfaces E1,E8, E2, E111, two of which bear on corresponding seats in t-hevalve-casing and limit the travel of the ltltl pea valve in onedirection, the other two bevel surfaces also bearing on correspondingseats in the valve-casing and limiting the travel of the valve in theopposite direction. When the valve is seated in one position, the supplyof motive fluid to one end of the cylinder and the exhaust from theopposite end of the cylinder are cut off' by the valve lapping over theports which are also sealed by the beveled seats of the valve bearing onthe beveled seats of the valve-casing. In this position of the valve,the exhaust to the first mentioned end of the cylinder and the supply offluid to'the opposite end of the cylinder is open. When the valve isseated in the opposite direction, the conditions are reversed and ineither position of the valve there is no waste of motive fluid and thefluid can only pass to the desired end of the cylinder, since theexhaust passage therefrom is tightly sealed by the beveled seat of thevalve and the supply of fluid to the other end of the cylinder is sealedby the other beveled seat of the valve.

The valve shown herein has pressure surfaces E11, E12, at each end, andwhen the ports A12, A20, are of suliicient cross-section, the plugs A21,22, removed and passages J, J sealed, the surfaces E11, E12 are alwayssubject to an equal fluid pressure tending to move the valverespectively in opposite directions. These pressure surfaces arepreferably made of equal areas so that the pressure on one of saidsurfaces tending to move the valve in one direction will be balanced bythe pressure on the other end of the valve tending to move it in theopposite direction.

With this arrangement of the passages A19, A20 there canV be no waste ofmotive fiuid past the convex sliding surfaces at the ends of the valvebecause when the valve is in either position, as for instance as shownin Fig. 3, the pressure in the annular chamber A11 at the inner end ofthe convex sliding surface is equal to the pressure at the left handside of the valve, and there is no tendency of the fluid at the leftouter end of the valve to pass by said surface, and at the right side ofthe valve the pressure in the annular chamber A15 at the inner' end ofthe convex surface is equal to the pressure on the right outer end ofthe valve. It will be thus understood that the convex sliding surfacesof the valve serve to guide the valve to its seats and overlap the portswhen the valve is moving from one position to the other but that thenicety of the lit of said surfaces and the wear thereof does not affectthe efficiency of the valve to prevent the escape of motive fluidthrough the exhaust-ports when the valve has reached its seated positionin either direction. While this arrangement of the passages r 12, A20,is preferred in order to prevent any waste of fluid that may leak pastthe convex surfaces at the ends of the valve, it will be understood thatsaid passages may be omitted and the opposite ends of the valve-casingconnected by a communicating passage in any suitable manner. `When thevalve is to be operated wholly by mechanical means, the ends of thevalve-casing may be open directly to the atmosphere, and the passagesA12, A2, closed tightly by suitable plugs. But in the latter case anyfluid that may leak past the convex sliding surfaces at the ends of thevalve will be wasted.

To assemble the valve in position in the valve-casing, the part E2 isplaced in position in the section A; the parts E, E3 are placedrespectively in the heads A11, r 1. The heads are placed in positiononthe section A and the bolt E4 is then inserted through the parts ofthe valve and secured by the nut E13, the end of the bolt being`rivetedover slightly to prevent t-he nut from unscrewing, or the boltmay be provided with a suitable lock-nut. The plates C', C2 are placedin position and secured by the bolts D, D2, D1. The surfaces of thesections and plates are finished to bear evenly to prevent leakage. Theseats of the valve and valve-casing may be lapped while in assembledposit-ion to bear perfectly.

The valve may be actuated in different ways. In the present instance Ihave `shown an internally operated tappet or rocker-arm F pivotallymounted on the pin G secured in the cylinder B, said tappet being movedin opposite directions by the beveled shoulders II', H2 of the piston H.The tappet is provided on its upper side with a flexible extension INwhich engages ,the sides of an annular groove E11 in the large diameterof the valve. The extension E is preferably formed integral with thetappet and is made with a cross-section that is adapted to form a'spring` or yielding connection between the valve and the piston.

One object of providing a yielding connection between the valve and thepiston is lo overcome the difficulty that would otherwise be experiencedin adjusting and maintainingthe throw or movement of the connection ortappet so that it would be exactly equal tothe proper travel or thedistance bctween the opposite seats of the valve-casing that is shownand described herein. It will be apparent that with a rigid connection aslight wear or lost motion would result. in the valve not seatingproperly. By employing a yielding connection I am enabled to make themovement or throw of the connection somewhat greater than the travel ofthe valve and thereby provide for wear and lost motion that may occurfrom long service.

Another very important feature is that by providing a yieldingconnection in combination with the novel valve herein shown anddescribed I am enabled to overcome the dead point in the travel of thepiston with a mechanically operated valve as will be herein` afterdescribed.

The recess B1 in the wall of the cylinder is always in communicationwith the passage A10 and the openino` A10 which as hereinbefore statedis preferably the exhaust opening. It will be apparent that the fluidpressure may be supplied through the opening A10 and the exhaust beconnected to the opening A0 but in the latter case when the valve isseated in either position, there will be a comparatively largeunbalanced area against which the motive fluid acts to hold the valve inseated position. When the motive fluid is supplied through the openingA0, as in Fig. 8, and the valve is seated in either position, theunbalanced area is equal to the dierence in area between the large andsmall diameters of the seat, being approximately equal to the area ofthe seat, and in practice it has been found that the power required tostart the valve from its seat is a great deal less than the powerrequired to move the unbalanced slide valves that are largely employedin apparatus of this character. As hereinbefore stated the pressuresurfaces of the valve are preferably of equal area. When the valve isnot in contact with its seat it is balanced. Then seated in eitherdirection the motive fluid tends to seat the valve and hold it in seatedposition. This is a very importantfeature and may be taken advantage ofto determine the speed at which the valve travels from one position tothe other independent of the speed at which the piston moves. lith atappet moved valve as ordinarily constructed and arranged, the speed atwhich the valve moves from one position to the other bears some fixedrelation to the speed of the piston and the piston must have suiiicientmomentum to carry the valve past the dead point.

lith the construction herein shown, when the tappet is moved by thepiston, the flexible extension F tends to move the valve in the samedirection in which the piston is moving, but the motive fluid tends tohold the valve to its seat, and the end of the extension lags behind thepiston until the tension exerted on the valve is suflicient to start thelatter from its seat. As soon as the valve moves, however, the motivefluid acts on the area that was previously seated and the valve is nowbalanced and moves freely so that the tension being exerted by theextension F snaps the valve over into the opposite position. The speedas which the valve moves from one position to the other may be varied byproportioning the cross-section of the extension F with relation to thearea of the valve seats.

Then the valve is wholly actuated by me- `motive fluid is constantlyadmitted.

chanical means, the operation is as follows: The piston being in theposition shown in Fig. l, the motive fluid is supplied through theopening A0 and passes by the surface E7 of the valve to the passages a,A in the valve-casing to the passage B2 leading to the left hand side ofthe cylinder to move the piston in the opposite direction. The exhaustfluid from the right hand end of the cylinder passes through the passageB in the wall of the cylinder into the passages A0, a0, in thevalve-casing and past the surface E0 of the valve into the passage A1and out through the opening A10. lhen the fluid pressure is beingsupplied to the passage A, it is prevented from escaping to the exhaustpassages by the bevel seat EH of the valve and the motive fluid isprevented from escaping' to the passage A2 by the bevel seat E10 of thevalve. The valve is held against said beveled seats by the pressure offluid against the unbalanced area of the seat E1. Then the shoulder H ofthe piston comes into contact with the left hand end of the tappet andmoves the latter, the tension of the extension F overcomes theresistance of the fluid pressure holding the valve to its seat and theposition of the valve is reversed. The motive fluid will now be suppliedpast the surface E10 of the valve to the passages a2, A2 and B3 to theright hand end of the cylinder to drive the piston in the oppositedirection. The exhaust fluid from the left hand end of the cylinder willescape through the passages B2, A', a2 past the surface E8 of the valveto the passage A10 and through the opening A10. The escape of fluid tothe exhaust passages is meantime prevented by the surfaces E7 and E0 ofthe valve. The valve is held in seated position by pressure on theunbalanced area of the surface E10 of the valve. When the shoul der H2of the piston comes into contact with the right hand end of the tappet,the valve will be moved to the position shown in Figi..

By providing the cylinder with the ports K, K connected respectivelywith opposite ends of the valve-casing by the passages represented bythe dotted lines J, J the valve may be operated wholly or partially byfluid pressure. In the latter case the pressure on one end of the'valve, that is in excess of the pressure of the opposite end of thevalve will assist or supplement the action of the tappet to move thevalve.

As hereinbefore stated, the passages A20, A21 are of small diameter.This is necessary in order to prevent a waste of fluid when either endof the valve is open to the chamber A10 through the passage J or J. Theoperation is the same as is usual with fluid actuated valves havingpressure surfaces of equal area to which the The pressure is exhaustedfrom one end of the valve to allow the pressure on the other end to movethe valve. lVhen the piston is in the position shown in Fig. l the portK is uncovered and the fluid from the left hand side of the valve isfree to exhaust into the space 1 being in communication through B4, i*25, A2. The port K being covered by the piston, the fluid supplied tothe right hand end of the valve through the small pas sage AF* isprevented from escaping and its pressure is exerted upon said end tomove the valve to the left hand side of the valve casing. When thepiston moves toward the right hand side of the cylinder, the port K iscovered to prevent the escape of iiuid and the port K is uncoveredallowing the escape of fluid whereby the valve is moved toward the righthand side of the casing. The ports are arranged so that when theshoulder H of the piston engages the left side of the tappet, theshoulder H2 of the piston will be passing over the port K to allow theescape of fluid. lVhen the shoulder H2 engages the right side of thetappet the shoulder H will be passing over the port K to allow theescape of fluid. It will be understood that when t-he piston engages thetappet to move the valve in either direction the fluid will be exhaustedfrom one end of the valve and the fluid pressure on the opposite end ofthe valve will assist the tappet to move the valve in the requireddirection. It will be seen that t-he tappet has very little work to do,which is a great advantage when employed in connection with a rapidlymoving piston. The tappet serves, however, to control the movement ofthe valve and prevent the delayed or irregular opening and closing ofthe ports through which the motive iiuid is supplied and exhausted whichis common with fluid actuated valves.

In ordinary piston valves the pressure surfaces against which the motivefluid acts to balance the valve or in some types to move the valve inopposite directions, do notact directly to close or seal the admissionand exhaust-ports, and the efficiency of the valve varies according tothe nicety of the lit of cylindrical or convex sliding surfaces of thevalve in the bore of the valve-casing when covering or lapping over theports leading from the valve-casing to opposite ends of the cylinder orto the exhaust-ports connected with the atmosphere. With the valveherein shown the pressure surfaces also act to seal the admission andexhaust ports and the efficiency of the valve when in seated position ineither direction does not depend on the fit of the convex bearingsurfaces, but upon the accurate timing and bearing of the pressuresurfaces on the corresponding seats of the valve-casing, the contactingsurfaces respectively limiting the travel of the valve in oppositedirections.

It will be understood that the pressure surfaces which limit the travelof the valve and against which the motive fluid acts to alternatelypress the valve in opposite di rections do not coperate with the fluidpressure to actuate the valve. The action of the fluid on said surfacesdoes not tend to move the valve but to resist its movement or press itin the opposite direction, when one of said surfaces is subject to fluidpressure and the opposing surface is not subject to such pressure. Thevalve is at the limit of its movement at this time and cannoty move inthe direction in which the fluid pressure tends to move it. As soon asthe valve moves in the opposite direction7 oneof the opposing surfaceswill present an equal area and the opposing surfaces are now balanced bythe fluid acting on equal areas and the fluid does not tend to move thevalve.

I claim as my invention:

l. In apparatus of the character described, a cylinder and piston, avalve-casing having ports through which motive fluid is sup plied to therespective ends of the cylinder, a valve having sliding bearing surfacesfitting the bore of the valve-casing which alternately overlap anduncover said ports to admit motive fluid to opposite sides of thepiston, said valve having also other surfaces which act to prevent thepassage of fluid through said ports.

2. In apparatus of the character described, a cylinder and piston, avalve-casing having two sets of ports communicating with passagesleading to the cylinder through which the motive fluid is supplied toand exhausted from the respective ends of the cylinder, a valve havingsliding bearing surfaces which alternately overlap and uncover saidports to admit and exhaust iuid to and from opposite sides of thepiston, said valve having also other surfaces which act to prevent thepassage of fluid through said ports.

3. In apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with oppositeends of the cylinder, said passages communicating respectively with twosets of ports in the valve-casing, a valve having sliding bearingsurfaces which alternately overlap and uncover said ports to admit andexhaust fluid to and from opposite sides of the piston, said valvehaving also other sur` faces which act to prevent the passage of fluidthrough said ports.

li. In apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating` respectively with oppositeends of the cylinder, and provided with ports communicating with therespective passages, a valve having sliding bearing surfaces whichalternately overlap and uncover said ports to admit motive fluid toopposite ends of the cylinder, the ports communicating with 011e @11d ofthe cylinder beE ing covered by the sliding surfaces of the valve beforethe ports communicating with the opposite end are uncovered, said valvehaving other surfaces which act to prevent the passage of fluid throughsaid ports.

5. In apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with oppositeends of the cylinder, and provided with ports communicating with therespective passages, a valve having sliding bearing surfaces Whichalternately overlap and uncover said ports to exhaust the fluid fromopposite ends of the cylinder, the ports communicating with one end ofthe cylinder being covered by the sliding surfaces before the portscommunicating with the opposite end are uncovered, the valve havingother surfaces which act to prevent the passage of fluid through saidports,

6. In apparat-us of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with oppositeends of the cylinder, said passages communicating respectively with twosets of ports in the valve-casing through one set of Which the fluid issupplied to and exhausted from the respective ends of the cylinder, avalve having sliding bearing surfaces which cont-rol said ports, theports through which the fluid is supplied being closed by the slidingsurfaces of the valve before the exhaust ports are uncovered, the valvehaving other surfaces which respectively limit the travel of the valvein opposite directions and act to prevent the escape of fluid past thesliding bearing surfaces of the valve.

7. In apparatus of the character described, a cylinder and piston, avalve-casing having ports through which motive fluid is supplied to therespective ends of the cylinder, a valve having opposing pressuresurfaces against which the motive fluid acts tending topress the valvein opposite directions and provided with sliding` bearing surfacesVwhich alternately overlap and uncover said ports, said valve havingannular surfaces which also act to prevent the passage of fluidrespectively through said ports.

8. In apparatus of the character described, a cylinder and piston, avalve-casing having two sets of ports communicating with passagesleading to the cylinder through which the motive fluid is supplied toand exhausted from the respective ends of the cylinder, a valve having`opposing pressure surfaces Vagainst which the motive fluid acts tendingy to press the valve in opposite directions and provided with slidingbearing surfaces which alternately overlap and uncover said ports, saidvalve having annular surfaces intermediate the ends of the valve whichalso act alternately to prevent the passage of fluid respectivelythrough said ports.

9. In apparatus of the character described,

a cylinder and piston, a. valve-casing having passages communicatingrespectively with opposite ends of the cylinder, each of said passagescommunicating respectively with two ports in the valve-casing throughone of which the fluid is supplied to and through the other of which thefluid is exhausted from the respective end of the cylinder, a valvehaving opposing pressure surfaces against which the motive fluid actstendingr to press the valve in opposite directions and provided withsliding bearing surfaces which control said ports, the ports throughwhich the fluid is supplied being closed by the sliding surfaces of thevalve before the exhaust ports are uncovered, said pressure surfacesacting to respectively limit the travel of the valve in oppositedirections and to prevent the escape of fluid past the sliding bearingsurfaces of the valve.

l0. In apparatus of the character described, a cylinder and piston, avalve-casing having ports through which motive fluid is supplied to therespective ends of the cylinder,r a valve having opposing pressuresurfaces against which the motive fluid acts to press the valve inopposite directions and provided with sliding bearing surfaces which fitthe bore of the valve-casing and alternately overlap and uncover saidports` said valve having also other surfaces which alternately act toprevent the passage oi Huid through said ports.

ll. In apparatus of the character described, a cylinder and piston, avalve-casing having two sets of ports through which motive fluid issupplied to and exhausted from the respective ends of the cylinder, avalve having opposing pressure surfaces against which the motive fluidacts to press the valve in opposite directions and provided with slidingbearing surfaces which alternately overlap and uncover said ports` saidvalve having also other surfaces which alternately act to prevent. thepassage of fluid through said ports.

l2. In apparatus of the cha facter described. a cylinder and piston, avalve-casing having passages communicating respectively with theopposite ends of the cylinder, said passages communicating with two setsof ports respectively in the valve-casing, a valve having opposingpressure surfaces against which the motive fluid acts to press the valvein opposite directions and provided with sliding bearing surfaces whichalternately overlap and uncover said ports, said valve having also othersurfaces which alternately act to prevent the passage of fluid throughsaid ports.

13. In apparatus of the character described, a cylinder and piston, a,valve-casing having passages communicating respec tively with theopposite ends of the cylinder and arovided with ports coninninicatinfT,l L b with the respective passages, a valve having opposing pressuresurfaces against which the motive fluid acts to press the valve inopposite directions and provided with sliding bearing` surfaces Whichalternately overlap and uncover' said ports to admit motive fluid toopposite ends of the cylinder', the ports communicating with one end ofthe cylinder being covered by the sliding surfaces of the valve beforethe ports communicating With the opposite end of the cylinder areuncovered, said valve having other surfac-es which respectively limitthe travel of the valve in opposite directions and act to prevent theescape of fluid past the sliding bearing surfaces of the valve.

14. In apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with theopposite ends of the cylinder and provided with ports con'imunicatingwith the respective passages, a valve having` opposing pressure surfacesagainst Which the motive fluid acts to press the valve in oppositedirections and provided with sliding bearing surfaces which alternatelyoverlap and uncover said ports to exhaust fluid from opposite ends ofthe cylinder, the ports comi'mmieating with one end of the cylinderbeing' covered by the sliding surfaces of the valve before the portcommunicating With the opposite end of the cylinder is uncovered, the`valve having other surfaces which respectively limit the travel of thevalve in opposite directions and act to prevent the escape of fluid pastthe sliding bearing surfaces of the valve.

l5. In apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with theopposite ends of the cylinder, said passages communicating With two setsof ports respectively .in the valve-casing, through one set of which themotive fluid is supplied to and exhausted from the respective ends ofthe cylinder, a valve having opposing pressurc surfaces against whichthe motive fluid acts to move the valve in opposite directions andprovided With sliding bearing surfaces which control said ports, theports through which motive fluid is supplied being closed by the slidingsurfaces of the valve. before the exhaust-ports are uncovered, the valvehaving other surfaces which respectively limit the travel of the valvein opposite directions and act to prevent the escape of fluid past thesliding bearing surfaces of the valve.

16. ln apparatus of the character described, a cylinder and piston, avalve-casing having ports through which motive fluid is supplied to therespective ends of the cylinder, a valve having sliding bearing surfaceswhich fit the bore of the valve-casingl and alternately overlap anduncover saidv bore the veuve-casing and alternately ports, the valvehaving pressure surfaces Which respectively limit the travel of thevalve in opposite directions and act to prevent the escape of fluid pastthe sliding bearing surfaces of the valve, and means independent of saidpressure surfaces for actuating the valve.

l?. In apparatus of the character' described, a cylinder and piston, avalve-casing having tivo sets of ports through which motive fluid issupplied to and exhausted from the respective ends of the cylinder, avalve having sliding bearing surfaces which alternately overlap anduncover said ports, the valve having pressure surfaces whichrespectively limit the travel of the valve in opposite directions andact to prevent the escape of fluid past the sliding bearing surfaces ofthe valve, and means independent of said pressure surfaces for actuatingthe valve.

18. ln apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with oppositeends of the cylinder, said passages communicating respectively With twosets of ports in the valve-casing, a valve having sliding bearingsurfaces which alternately overlap and uncover said ports, the valvehaving pressure surfaces which respectively limit the travel of thevalve in opposite directions and act to prevent the escape of fluid pastthe sliding bearing surfaces of the valve, and means independent of saidpressure surfaces for actuating the valve.

19. In' apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with oppositeends of the cylinder, said passages communicating respectively With twosets of port-s in the valve-casing through one set of Which the fluid issupplied to and exhausted from the respective ends of the cylind-er, avalve having sliding bearing surfaces Which control said ports, theports through which the fluid is supplied being closed by the valvebefore the exhaust-ports are uncovered, said valve having pressuresurfaces which respectively limit the travel of the valve in oppositedirections and act to prevent the escape of fluid past the sliding`bearing surfaces of the valve, and means independent of said pressuresurfaces for actuating the valve.

l'n appa atus of the character described, a cylinder' and piston. avalve-casing having' tivo sets of ports through which the motive fluidis supplied'to and exhausted from the respective ends of the cylinder,:i valve. having opposing pressure surfaces against which the motiveacts to press the valve in opposite directions and provided vrithsliding bearing surfaces which fit thel overlap and uncover said ports,the valve having pressure surfaces which respectively limit the travelof the valve in opposite directions and act to prevent the escape ofHuid past the sliding bearing surfaces of the valve, and meansindependent of said pressure surfaces for actuating the valve.

2l. In apparatus of the character described, a cylinder and piston, avalve-casing having passages communicating respectively with oppositeends of the cylinder, said passages communicating with two sets of portsin the valve-casing through which the motive fluid is respectivelysupplied to and exhausted from the cylinder, a valve having bearingsurfaces sliding in the bore of the valve-easing which alternatelyoverlap and uncover said'ports and other surfaces which respectively7limit the travel of the valve in opposite directions and act to preventthe escape of fluid past the sliding bearing surfaces of the valve.

22. In apparatus of the character de scribed, a cylinder and piston, avalve-casing having passages communicating respectively7 with oppositeends of the cylinder, said passages communicating with two sets of portsin the valve casing through which the motive fluid is respectivelysupplied tol and exhausted from the cylinder, a valve having bearingsurfaces slidingvin the bore of the valve-casing which alternatelyoverlap and uncover said ports, the valve having opposing pressuresurfaces against which the motive fluid alternately acts tending topress the valve in opposite directions and hold it in seated position,said opposing surfaces acting respectively to limit the travel of thevalve in opposite directions and to prevent the escape of fluid past thesliding bearing surfaces of the valve.

23. In apparatus of the character described, a cylinder and piston, avalve-casing having ports -communicating respectively with opposite endsof the cylinder, a valve having sliding bearing surfaces movable in saidcasing which alternately overlap and uncover the ports for controllingthe admission of motive fluid through said ports to operate the piston,said valve having opposing pressure surfaces intermediate the ends ofthe valve against one of which the motive fluid acts tending to pressthe valve in one direction and hold the opposite surface in seatedposit-ion and when the valve is at the end of its movement in theopposite direction the motive fluid acting against said opposite surfaceto press the firstm-entioned surface in seated position, said pressuresurfaces respectively limiting the travel of the valve in oppositedirections` and means controlled by the movements of the piston foractuating the valve.

24. ln apparatus of the character dc-` scribed, a cylinder and pistone,valve-casing having ports communicating respectively with opposite endsof the cylinder, a valve having sliding bearing surfaces movable in saidcasing which alternately overlap and uncover the ports for controllingthe admission of motive fluid through said ports to operate the piston,said valve having opposing pressure surfaces against one of which theinotive fluid acts tending to press the valve in one direction and holdthe opposite surface in seated position and when the valve is at the endof its movement in the opposite direction the motive fluid actingagainst said said opposite surface to press the first mentioned surfacein seated position, said pressure surfaces respectively limiting thetravel of the valve in opposite directions. the contacting surfaceswhich limit the travel of the valve acting to prevent' the admission ofmotive fluid respectively to opposite ends of the cylinder, and meansindeliendent of said pressure surfaces for actuating the valve.

25. In apparatus of the character described, a cylinder and piston, avalvecasing, a valve having sliding bearing surfaces movable in saidcasing for controlling the movements of the piston, said valve-casinghaving ports and passages communicating respectively with opposite endsof the c vlinder, said ports and passages being alternately cut off fromcommunication with liuid pressure supply and with exhaust passages inthe valve-easing by said sliding bearing surfaces on reciprocation ofthe valve which alternately overlap and uncover the ports, the motivefluid acting alternately on opposing pressure surfaces of the valve.tending to maintain it in seated position at each end of its movement.said opposing pressure surfaces of the valve abutting against internalshoulders in the valve-easing to respectively limit the travel of thevalve in opposite directions and respectively prevent the admission ofmotive fluid to opposite ends of the cylinder.

26. ln apparatus of the character described, a cylinder and piston` avalve-casing, a valve mo fable in said casing. said valve having slidingconvex bearing surfaces which fit the bore of the valve-casing.r saidvalve-casing being provided with inlet ports and with ports incommunication respectively with opposite ends of the cylinder. thesliding convex bearing surfaces of the valve alternately overlapping anduncovering the inlet ports to the bore of the valve-asing` the valvehaving annular surfaces which respectively limit the travel of the valvein opposite directions, the contacting surfaces which limit the travelof the valve also act ing to prevent. the passage of fluid through saidports.

Q7, ln apparatus of the character described. a cylinder and piston. avalve-casing, a valve movable in said casing, said valve having slidingconvex bearing surfaces, said valve-casing being provided With inletports and exhaust ports, the valvecasinghaving ports which are incommunication respectively with opposite ends of the cylinder, thesliding co-nvex bearing surfaces of the valve alternately overlappingand uncovering the inlet and exhaust-ports to the bore of thevalve-casing, one set of ports being closed by the valve before theother set of ports are uncovered, the valve having annular surfacesWhich limit the travel of the valve respectively in opposite directions,the contacting surfaces which limit the travel of the valve also actingto prevent the passage of fluid through said inlet and exhaust-ports.

28. In apparatus of the character described, a cylinder and piston, avalve-casing, a valve movable in said casing and having convex bearingsurfaces, said valve-casing heilig provided With inlet and exhaustports,the convex bearing surfaces of the valve alternately overlapping anduncovering said ports to the bore of the valvecasing when the valvemoves from one position to the other, said ports being arranged so thatin the intermediate position of the valve the ports Will be closed, saidvalve having annular surfaces intermediate of the ends of the valveWhich also act to prevent the passage of fluid through said ports.

29. In apparatus of the character described, a cylinderl and piston, avalve-casing, a valve movable in said casing and having convex bearingsurfaces, said valvecasing being provided With inlet and exhaust-ports,the convex bearing surfaces of the valve alternately overlapping anduncovering said ports to the bore of the valvecasing when the valvemoves from one position to the other, said valve having` annularsurfaces which respectively limit the travel of the valve in oppositedirections, the contacting surfaces which limit the travel of the valveacting alternately to prevent the passage of fluid through said ports.

30. In apparatus of the characterl described, a cylinder and piston, avalve-casing, a valve movable in saidcasing, and having convex bearingsurfaces, said valvecasing being provided with inlet and exhaust-ports,the convex bearing surfaces of the valve alternately overlapping anduncovering said ports to the bore of the valvecasing When the valvemoves from one position to the other, said ports being arranged so thatthey are closed when the valve is at the intermediate point of itstravel, said valve having beveled surfaces which limit the travel of thevalve respectively in opposite directions, the contacting surfaces ofthe valve acting alternately to prevent the passage of Huid through saidports.

31. In apparatus of the character described, a cylinder and piston, avalve casing, a valve movable in said casing and having convex bearingsurfaces, said valve casing being provided vvithinlet and exhaust ports,the convex bearing surfaces of the valve alternately overlapping anduncovering said ports to the bore of the valve casing when the valvemoves from one position to the other, said valve having annular surfacesWhich respectively limit the travel of the valve in opposite directions,the contacting surfaces Which limit the travel of the valve acting toprevent the escape of fluid that may leal: past the convex bearingsurfaces of the valve when the latter is in seated position and meansindependent of said annular surfaces for actuating the valve.

32. In apparatus of the character described, a cylinder and piston, avalve casing, a valve movable in said casing, and having convex bearingsurfaces, said valve casing being provided vvith inlet and exhaustports, the convex bearing surfaces of the valve alternately overlappingand uncovering said ports to the bore of the valve casing When the valvemoves from one position to the other, said ports being arranged so thatthey are closed when the valve is at the intermediate point of itstravel., said valve having beveled surfaces Which limit the travel ofthe valve respectively in opposite directions, the contacting surfacesof the valve acting to preventthe escape of Huid that may leak past theconvex bearing surfaces of the valve when the latter is in seatedposition and means independent of said beveled surfaces for actuatingthe valve.

33. In apparatus of the character described, a cylinder and piston, avalve casing, a valve movable in said casing and having convex bearingsurfaces, said valve casing being provided With inlet and exhaust ports,the convex bearing surfaces of the valve alternately overlapping anduncovering said ports to the bore of the valve casing When the valvemoves from one position to the other, said valve having annular surfaceswhich respectively limit the travel of the valve in opposite directions,the contacting surfaces Which limit the travel of the valve acting toprevent the escape Vof iuid that may leak past the convex bearingsurfaces of the valve When the latter is in seated position and meansfor mechanically operating said valve.

34C. In apparatus of the character described, a cylinder and piston, avalve casing, a valve movable in said casing, and having convex bearingsurfaces, said valve casing being provided with inlet and exhaust ports,the convex bearing surfaces of the valve alternately overlapping anduncovering said ports to the bore of the valve casing When the valvemoves from one position to the other, said ports being arranged so thatthey are closed When the valve is at the intermediate point of itstravel, said valve having beveled surfaces Which limit the travel of thevalve respectively in opposite directions, the contacting surfaces ofthe valve acting to prevent the escape of fluid that may leak past theconveX bearing surfaces of the valve when the latter is in seatedposition and means con- 10 trolled by the movements of the piston formechanically operating said valve.

In testimony Wliereotl I aiiix my signature, in presence of twoWitnesses.

GEORGE L. BADGER. Witnesses:

VILLIAM A. COPELAND, ALvm TARR.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C."

